Type of Insects That Infest Mimosa Pudica

Sensitive plant’s leaflets fold and droop at night.

Mimosa pudica, commonly called the sensitive plant, will fascinate you with its sensitive leaflets that fold up and droop when you touch them. Outdoors, sensitive plant grows in U.S. Department of Agriculture plant hardiness zones 10 and above. Despite its name, this plant is not difficult to care for, but it is vulnerable to sap-, wood- and foliage-feeding insects.

Sap-Feeding Insects

Sap-feeding insects can be a problem for sensitive plant and its close relatives, particularly acacia psyllids, which feed on the fluids in the leaves, shoots and buds. Psyllids secrete a white wax and produce honeydew, which attracts ants and promotes sooty mold growth. Severe infestations can cause reduced vigor, distortion and discoloration of leaves and twigs, and dieback. Most healthy plants tolerate extensive psyllid feeding, so maintaining plant health through proper care can prevent serious damage to sensitive plants. Spider mites may also be a problem, as they cover sensitive plant leaves in fine webbing. They also feed on plant sap but are arachnids, which are not technically insects. Spider mite feeding causes a stippling of white dots to appear. Leaves may take on a bronze color and as feeding continues, the foliage turns yellow or reddish and drops.

Wood-Boring Insects

Sensitive plant may be infested by carpenterworms (Prionoxystus robiniae), which are wood-boring caterpillars that can cause significant damage. The larval stage feeds on the sapwood within the inner bark. Signs of early infestation include dark sap spots on the trunk. The larvae also expel frass, or excrement, out of the entrance holes. Their hairy bodies are typically greenish-white in color, with a brown head. Adult carpenterworms are large moths, with mottled black and gray wings.

Foliage-Feeding Insects

Sensitive plant is vulnerable to foliage-feeding caterpillars, primarily the mimosa webworm (Homadaula anisocentra). This insect pest spins gray webs around the foliage before feeding on it and can cause complete leaf loss on your plant. The eggs of the mimosa webworm are oval and white, but turn pink when the gray to brown larvae are ready to hatch. Larvae of this pest have five white stripes on their bodies, and their pupae are yellowish-brown. The adult silver-gray moth has black dots covering the wings, but is rarely seen. Mimosa webworms and other foliage-feeding caterpillars skeletonize the leaves of many ornamentals, but damage in healthy plants is usually only cosmetic.

Management and Prevention

Applying insecticides containing azadirachtin, or neem oil, insecticidal soap or horticultural oil, can provide temporary control of psyllid infestations. Systemic insecticides, such as imidacloprid, can also provide control, but should be a last resort because they can contribute to outbreaks of spider mites. If spider mites become a problem, they typically have many natural enemies that help keep populations limited. These include the Western predatory mite (Galendromus occidentalis), Phytoseiulus mite species, sixspotted thrips (Scolothrips sexmaculatus), pirate bugs, bigeyed bugs and lace­wing larvae. Insecticidal oils or soaps can also be effective in treating severe spider mite infestations. To control carpenterworms, commercially available beneficial nematodes such as Steinernema feltiae or Steinernema carpocapsae can be effective. Proper sanitation, such as clearing leaf debris away from your sensitive plant, can prevent infestations of both carpenter worms and foliage-feeding caterpillars such as the mimosa webworm. Pick off caterpillars as you see them and scrape eggs masses from your plant into a bucket of soapy water to control existing infestations. Sensitive plants already infested with caterpillars may benefit from applications of Bacillus thuringiensis, which can reduce caterpillar populations if applied to newly hatched larvae.